Even in boom times, the salaryman – that symbol of modern Japan – was always a bit of a joke.

With his ill-cut suits and boring ties, his thick spectacles and thinning hair, he was the object of amused scorn at home and abroad. With the collapse of the Japanese economy in the 1990s even his prestige as a corporate warrior deserted him.

But the salaryman is undergoing an astonishing transformation, from company dork to a figure of glamour, cool and sex appeal. In glossy magazines, exquisite shops and even beauty parlours, businesses across Japan are competing to win the custom of the men also known as oyaji, which means uncle but has come to stand for middle-aged men in general.

This week Tiffany & Co, the New York jeweller, opened its first shop dedicated to male customers in the Isetan department store in Tokyo. Yesterday a men-only branch of United Arrows, a company that is catering increasingly to the oyaji customer, opened in the city’s gleaming Roppongi Hills complex.

The Japanese language has minted new words to describe the new breed of middle-aged metrosexuals. Choiwaru oyaji – “somewhat bad uncles” – are salarymen with attitude, the Tokyo equivalents of George Clooney or Charles Dance. Koyaji (“small uncles”) are the junior middle-aged, Japanese Hugh Grants and Brad Pitts, who may no longer be young, but still cut a dash. The tone of the revival is summed up in the pages of the naughty uncles’ bible, the magazine Leon, whose circulation has risen from a few thousand seven years ago to 100,000 a month.

Its pages are filled with images of good-looking, middle-aged models in exquisite clothes, cavorting with young and attractive women.

“There is no question that Japanese men are getting more stylish,” says Tatsuyoshi Endo, of the cosmetics manufacturer Shiseido. “In the past, salaryman generally suggested someone who smoked a lot, drank a lot and was on the chubby side, but who didn’t feel bad about it. Now people realise that it is off-putting to others if you stink of cigarettes or booze, and that a paunch doesn’t look very good.”

The reasons behind this national midlife crisis are tied up with Japanese history, demographics and the fortunes of the immediate postwar “baby boom” generation. To men educated in the atmosphere of austerity and militarism of the prewar and wartime period, manliness and fashion were mutually exclusive.

“The men identified as oyaji used to be the generation who remembered the ruins of the war, and never became big consumers,” Ichiro Kishida, the founder of Leon, said. “But today’s oyaji were surrounded with consumer products from their youth, and are confident about expressing their individual preferences.”

The blossoming of consumer goods aimed at men is a positive aspect of broader changes in society. Fifteen years ago, a university graduate could expect to work with a steadily rising income for the same company for life. But the collapse of the “bubble economy” in the early 1990s brought corporate collapse, mass redundancies and an air of insecurity and unpredictability.

There are other influences, among them Japan’s former Prime Minister, Junichiro Koizumi, who was individualistic by any standard, with his permed mane and love of Elvis Presley. Mr Koizumi instituted a national dress code known as “cool biz”, whereby salarymen took off their jackets and ties and companies saved energy by turning down the air-conditioning during Japan’s stifling summer.

“The old model is broken,” says Hirofumi Kurino, the creative director of United Arrows, which has launched a new chain of shops, Darjeeling Days, aimed at the older man. “Major companies went bankrupt, doctors went bankrupt, even the banks themselves went bankrupt. There used to be clear railway tracks in society; there aren’t any more. And nowadays you can be without a tie and a jacket and still be taken seriously. That’s a very drastic change for Japan.”

Oyaji style: What to give the salaryman who has everything

— A subscription to Leon, the telephone directory-size glossy magazine. The headline of its October issue reads: “Two watches are enough for an oyaji’s wrists”.

— An eyebrow trim at the Refinery, a British “grooming salon” which has opened a men-only branch in a Tokyo shopping centre.

— Deodorant oyaji talc, oyaji body mist and oyaji antiperspirant wipes from Shiseido, chemically formulated to eliminate the odours of ageing. The slogan for the products is: “Wow! Where did that smell go?”

— Cable subscription so he can watch Style Book, a TV magazine programme for dandyish salarymen. Its motto is: “Will satisfy the playful minds of men.”

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